Water cooled power head mounting for outboard motors



Sept. 4, 1962 E. c. KIEKHAEFER 3,052,087

WATER COOLED POWER HEAD MOUNTING FOR OUTBOARD MOTORS Filed Feb. 16, 1961 IN VEN TOR. Elmer 0. Kiekhaefer BY 2 ms fiYn Z MM United States Patent Office 3,052,087 Patented Sept. 4, 1962 3,052,087 WATER COOLED POWER HEAD MOUNTING FOR OUTBOARD MOTORS Elmer Carl Kiekhaefer, Cedarburg, Wis., assignor, by

mesne assignments, to Kiekhaefer Corporation, Chicago, 111., a corporation of Delaware Filed Feb. 16, 1961, Ser. No. 89,779 8 Claims. (Cl. 60-31) This invention relates to a power head mounting for outboard motors and particularly to a flexible partition or diaphragm sealing a lower exhaust passage from a power head chamber to prevent ingress of exhaust gases to the power head chamber from the exhaust passage.

Generally, outboard motors include an upper internalcombustion engine constituting the power head which is mounted upon the upper end of a hollow drive shaft and exhaust housing which carries a propeller unit at the lower end. A protective and decorative cowling encloses the power head and is also secured to the upper end of the exhaust housing. A drive shaft extends through the housing and couples the power head to the propeller. The exhaust gases from the internal-combustion engine are discharged into the hollow housing and pass downwardly and outwardly through a suitable port in the lower portion of the housing. The outboard motor is normally mounted to the aft end of a boat through a suitable swivel and clamp support.

The operation of the internal-combustion engine results in vibrations which tend to be transmitted to the boat through the mounting means. The vibrations are objec tionable to the occupants of the boat and are further detrimental to the normal life of the components of the outboard motor and of the boat. The problem of vibration is particularly severe with the larger and more powerful engines presently being developed and in use.

Various isolating mountings have been proposed for isolating or separating the power head vibrations from the balance of the motor and the boat. A highly desirable and satisfactory vibration isolating mounting for a power head is shown in United States Patent 2,909,031, which issued October 20, 1959, and which is entitled Vibration Isolation of Power Head. As disclosed therein, resilient mounts are disposed immediately between the power head and the lower drive shaft and exhaust housing. Such spacing of the power head from the drive shaft housing permits exhaust gases to back up into the cowling unless an adequate seal is provided. The above patent provides a special water-cooled flexible diaphragm spanning the opening to prevent movement of exhaust gases upwardly into the power head chamber defined by the cowling. An exhaust stack projects downwardly through and in sealing arrangement with an opening in the diaphragm to discharge the exhaust gases and the cooling water into the exhaust passage. A part of the cooling water is forced upwardly into cooling engagement with the separating partition to prevent abnormal heating of the diaphragm.

Although the above structure provides a highly satisfactory and improved mounting for the power head of an outboard motor, it has been found that under certain circumstances, overheating of the partition may occur. During running of the power head, the positive cooling action prevents overheating of the partition. When the engine stops, however, the cooling water is no longer forced into cooling engagement with the partition or diaphragm. The accumulated heat within the engine cowl tends to evaporate the coolant which was last sprayed upon the diaphragm and tends to subject it to the deteriorating effect of high temperatures. An excessive number of periods of overheating may adversely affect the characteristics of the partition.

The present invention is directed to an improved partition construction for a vibration mounted power head to essentially eliminate any undue heating of the diaphragm or partition structure both during the operation of the power head and after the power head has been stopped.

Generally, in accordance with the present invention, a cooling chamber is incorporated into the partition structure and connected in communication with the cooling system for the power head. The partition cooling chamber is so arranged that when the power head is stopped, the cooling water in the power head system maintains the partition cooling chamber substantially filled until all of the Water from the power head system is discharged. Consequently, the partition structure is provided with a positive cooling means for a length of time suflicient for cooling of the power head and surrounding members to a level which does not adversely affect the characteristics of the partition structure.

In accordance with another aspect of the present invention, the partition structure includes a pair of similar flexible diaphragm members spanning the opening between the drive shaft housing and the cowling and being disposed in sealing engagement with the adjacent surfaces thereof as well as the adjacent surfaces of the exhaust passage. Openings are provided in the exhaust stack to allow the cooling water of the power head system to flow into the cooling chamber formed by the vertically spaced diaphragms. During the operation of the power head, the cooling water will be circulated throughout the power cooling system and maintain cooling water within the partition cooling chamber. When the motor is stopped the water flows under the influence of gravity from the power head. The cooling chamber remains filled until such time as the cooling system in the power head proper has been drained. Therefore, for an appreciable period after stopping of the power head, the partition structure is cooled and the temperature of the power head and adjacent components decreases below a temperature normally detrimental to the partition structure.

The spaced diaphragms may be selected with maximum rigidity allowable with the desired flexing characteristic and thereby also constitute a pair of stabilizing members to increase the lateral stability of the resilient mounting of the power head upon the upper end of the drive shaft housing.

The present invention thus provides a means for vibration isolating of an outboard motor power head immediately adjacent the power head while maintaining efficient and positive separation of the exhaust passage from the power head chamber and for stabilizing the power head mounting in a lateral direction.

The drawing furnished herewith illustrates the best mode presently contemplated for carrying out the invention.

In the drawing:

FIG. 1 is a side elevational view of an outboard motor mounted on the stern or aft end of an outboard motor boat, with parts broken away and sectioned to clearly illustrate the present invention; and

FIG. 2 is a horizontal section taken on line 22 of FIG. 1.

Referring to the drawing, an outboard motor 1 is shown secured to the stern 2 of a boat, not otherwise shown, by a clamp 3. A swivel bracket 4 is secured to the clamp and to the motor 1 by suitable resilient mounts 5 to interconnect the outboard motor 1 to the boat. The resilient mounts 5 tend to isolate the vibrations of the outboard motor from the boat 2.

The outboard motor 1 is illustrated as including a lower drive shaft and exhaust housing 6 having fore and aft mounting flanges 7 and 8.

An internal-combustion engine or power head 9 is resiliently mounted as subsequently described upon the upper end of the drive shaft and exhaust housing 6. A protective and decorative cowling encloses the head 9 with a lower opening complementing the opening defined by the upper end of the housing 6. The cowling 10 rests directly upon the drive shaft housing 6 and includes flanges 11 and 12 superimposed upon the housing flanges 7 and 8.

The power head 9 is mounted on the drive shaft housing 6 by resilient mounts or blocks 13 which are disposed between integrally formed backets 14 which extend laterally from power head 9 and the upper surface of the cowling flanges 11 and 12. Bolt means 15 project through registered openings in brackets 14 and the aligned blocks 13 and flanges 11 and 12 and thread into suitably tapped openings in flanges 7 and 8 to connect the power head 9 to the drive shaft housing 6. The resilient blocks 13 essentially isolate the power head vibrations from the drive shaft housing 6.

The power head 9 includes a drive shaft 16 which is secured to the lower end of a crank shaft 17 and which depends coaxially through a crank case sealing neck 18 into the upper end of the housing 6. A drive shaft extension 19 is connected by an elastic coupling 20 to the lower end of shaft 16 to isolate power head vibrations from the drive shaft extension 19. An underwater unit 21 is secured to the lower end of the drive shaft housing 6 in accordance with known practice. The underwater unit 21 normally contains a bevel gear or the like, not shown, which couples a propeller 22 to the drive shaft extension '19 and thus to the output of the power head 9.

The internal-combustion engine or power head 9 includes an exhaust passage or port 23 for discharging the burnt gases from the power head 9. A tubular exhaust stack 24 is secured to the power head 9 and depends into the upper end of housing 6. The stack 24 includes a central exhaust passage 25 aligned with the exhaust port 23 to carry the exhaust gases into the drive shaft and exhaust housing 6. A housing discharge port 26 is secured to the trailing lower end of the exhaust housing 6 to discharge the exhaust gases to the atmosphere.

A partition structure including a pair of vertically spaced semi-flexible diaphragms 2'7 and 28, preferably of natural or synthetic rubber, is secured spanning the adjacent openings of the cowling 10 and the housing 6 to close the passage therethrough and prevent the exhaust gases from moving upwardly into the cowling 10.

The lower diaphragm 27 is disposed generally in the plane of the upper surface of the housing 6 and includes an outer bead 29 disposed within a clamping recess in the upper surface of the housing 6 including flanges 7 and 8. A clamping ring 30 rests upon the upper surface of the bead 29. Interconnecting of power head 9 and the cowling 10 to the housing 6 by bolt means 15 causes bead 29 to be compressed and hermetically seal the adjacent joint.

The diaphragm 27 includes openings aligned with and encircling the crank case sealing neck 18 and the exhaust stack 24. A bead 31 defines the opening adjacent the neck 18 and is disposed in liquid-tight engagement within a suitable encircling recess formed in the lower portion of the neck 18. Similarly, the opening in diaphragm 27 for the exhaust stack 24 is defined by a ring bead 32 which abuts against a lip 33 formed in alignment with the plane of the diaphragm 27 to hermetically seal the opening about the exhaust stack 24.

The upper diaphragm 28 is similarly formed and includes an outer bead 34 disposed within a recess in the upper surface of coupling flanges 11' and 12. A clamping ring 35 rests on the upper surface of the bead 34 and is drawn down into clamping engagement by suitable clamp bolts 36 which pass through aligned openings in ring 35 and diaphragm 28 and thread into suitably tapped openings, not shown, in the cowling flanges. The diaphragm 28 includes openings with reinforcing and sealing beads 37 and 38 abutting the neck 18 and the exhaust stack 24. The pair of diaphragms 27 and 28 hermetically seal the exhaust chamber formed by housing 6 from the power head chamber defined by cowling 10 to prevent exhaust gases from moving upwardly into the power head chamber.

The pair of diaphragms 27 and 28 are connected through the neck 18 and stack 24 to the power head 9. The diaphragms are formed with a limited flexibility allowing the power head vibration while maintaining sufficient stiffness to provide lateral or horizontal stability to the mounting of the power head 9.

The spaced diaphragms 27 and 28 define a partition cooling chamber 39 which is connected in communication or in circuit with a cooling system, not shown, within the power head 9.

A cooling water inlet line 40 is provided for supplying cooling water to the power head 9 during operation of the motor 1. The line 40 in accordance with known construction, extends from the underwater unit 21 upwardly through the exhaust housing 6 and into connection with the cooling system in the power head 9. A small pump, not shown, is provided within unit 21 for operation from shaft 19. A water discharge port 41 is provided in the lower end of the power head 9 immediately adjacent exhaust passage 23. The exhaust stack 24 includes, in the illustrated embodiment of the invention, an integrally formed encircling jacket providing a cooling chamber 42 aligned with and in communication with the discharge port 41 from the power head 9. A plurality of small discharge openings 43 are formed in the lowermost end of the stack 24 to discharge the cooling water from the chamber 42 into the exhaust stream where the heated water is carried outwardly and discharged through the port 26 in the lower portion of the housing 6.

In accordance with the illustrated embodiment of the invention, small interconnecting passages 44 are formed in the outer jacket wall of the stack 24 in alignment and in communication with the cooling chamber 39 formed by the spaced diaphragms 27 and 28.

During the operation of the outboard motor, the cooling water is pumped upwardly through the line 40* into the power head 9. The discharging water from the power head 9 passes downwardly through port 41 and through the stack cooling chamber 42 of the stack 24 and discharges outwardly through the small openings 43. The restricted discharge openings 43 establish a back pressure on the water in the power head 9 and maintain water pressure within the water jacket of the power head 9 and the stack 24. The water pressure further insures movement of water into the partition cooling chamber 39. Consequently, during the operation of the motor, a continuous reservoir of water is maintained within the partition structure .to maintain the diaphragms 27 and 28 at a desirable minimum temperature.

When the power head 9 is stopped, the pumping action also ceases and water no longer flows upwardly through line 40. The water in the power head 9 then drains outwardly through the discharge port 41 into the cooling chamber 42 of the stack 24 and then into the exhaust housing 6. Consequently, the cooling chamber 39 which is below the level of the power head 9 retains cooling water until such time as substantially all of the water in the power head 9 has drained therefrom. Subsequently, the water in the cooling chamber will also drain therefrom.

The period of time required for the power head 9 to drain provides sufllcient opportunity for the power head 9 and theadjacent components to dissipate the heataccumulated therein and consequently diaphragms 27f and28 are not subjected to abnormally high deterioratingtemr peratures.

If desired, the ports 44 may be disposed slightly above the diaphragm 27, as shown, to retain a residue of water in chamber 39 between the diaphragms after the engine is drained, thereby continuing the cooling effect by slow evaporation of the retained water. The cooling water within the diaphragm cooling chamber may also be discharged through small openings in the lower portion of the chamber within the scope of the present invention. Although the diaphragm is shown formed by spaced members, an integral structure having one or more cooling pockets or chambers may also be employed.

The present invention provides an improved cooling system for a separation or partition structure within an outboard motor and permits increasing the stability of a vibration-free mounting of the outboard power head.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. In an outboard motor adapted to have the lower end immersed in water and having a power head elastically mounted upon the upper end of a housing defining an exhaust chamber, an exhaust discharge means directing the exhaust from the power head into the exhaust chamber, a sealing means arranged to close the upper end of the exhaust chamber, said sealing means including resilient means for isolating the vibration of the power head and at least one cooling chamber, and means for introducing a coolant into the cooling chamber during operation of the power head and to maintain coolant in the cooling chamber after stopping of the power head.

2. In an outboard motor adapted to have the lower end immersed in water and having a power head disposed within a power head chamber defined by a cowling assembly and elastically mounted upon the upper end of a housing defining an exhaust chamber, the lower end of the cowling assembly being secured to the exhaust housing with communication between the power head chamber and the exhaust chamber and with an exhaust unit depending from the power head into the exhaust chamber, a flexible sealing member arranged to separate the power head chamber from the exhaust chamber, said sealing member including a cooling chamber, and means for introducing a coolant into the cooling chamber during operation of the power head and to maintain coolant in the cooling chamber for a substantial period after stopping of the power head.

3. In an outboard motor having a water-cooled power head disposed within a power head chamber defined by a cowling assembly and being elastically mounted upon the upper end of a drive shaft housing defining an exhaust chamber, the lower end of the cowling assembly being secured to the housing with an exhaust discharge means depending from the power head into the housing, a flexible sealing member arranged to separate the power head chamber from the exhaust chamber, said sealing member including a cooling chamber, and means to connect the cooling chamber into the cooling system of the water-cooled power head.

4. In an outboard motor having a water-coolant power head supported on and in spaced relation to the upper end of a hollow drive shaft housing defining an exhaust chamber with a cowling secured to the upper end of the drive shaft housing to enclose the power head, an exhaust unit and a drive shaft support depending from the power head through an opening into the drive shaft housing, a first flexible sealing member spanning the opening adjacent the exhaust unit and the drive shaft support and forming a liquid-tight joint with the adjacent surfaces, a second flexible sealing member spanning the opening in vertically spaced relation to the first flexible sealing member and forming a liquid-tight joint with the adjacent surfaces to define a cooling chamber between said members intermediate the length of the exhaust unit, said exhaust unit including a cooling jacket in communication with the first-named cooling chamber and having a discharge opening means in the lower end of the jacket to discharge the cooling water into the exhaust chamber, and means to supply coolant from the water cooling system of said power head to said jacket.

5. In an outboard motor having a water-cooled power head supported on and in spaced relation to the upper end of a, hollow exhaust housing with a cowling secured to the upper end of the housing to enclose the power head, an exhaust stack depending from the power head through an opening into the exhaust housing, a first flexible sealing member spanning the opening surrounding the exhaust stack and including an exhaust stack opening, means to seal the flexible sealing member to all adjacent surfaces including said exhaust stack, a second flexible sealing member spanning the opening surrounding the exhaust stack in vertically spaced relation to the first flexible sealing member and including an exhaust stack opening, means to seal the second sealing member to all adjacent surfaces including said exhaust stack and defining a sealing member cooling chamber with the first sealing member, said exhaust stack being jacketed to include an exhaust cooling chamber with a discharge opening means within the exhaust housing and below the sealing members, and port means connecting the sealing member cooling chamber to the exhaust cooling chamber.

6. In an outboard motor having a water-cooled power head supported by vibration isolating means upon the upper open end of a hollow drive shaft housing defining an exhaust chamber and having a cowling disposed over the power head with a lower open end secured in superimposed relation to the upper end of the drive shaft housing, a drive shaft neck depending from the power head through the superimposed cowling and housing openings, a jacketed exhaust stack laterally spaced from the neck and depending from the power head through the superimposed cowling and housing openings and having an encircling cooling chamber in the jacket thereof with discharge opening means in the lower portion of the stack, a first diaphragm spanning the opening in the drive shaft housing and extending between adjoining surfaces of the drive shaft housing and the cowling to releasably clamp the first diaphragm in position, said diaphragm having openings accommodating the drive shaft neck and accommodating the exhaust stack above the discharge openings and being in sealing engagement therewith, a second diaphragm spanning the opening in the cowling with the peripheral edge releasably attached in sealing engagement to the cowling and having openings accom modating the neck and stack and being in sealing engagement with the neck and the stack, and lateral ports in the outer jacket of said exhaust stack connecting the cooling chamber of the exhaust stack to the cooling chamber defined between said diaphragms.

7. In an outboard motor having a water-cooled power head supported by vibration isolating means upon the upper open end of a hollow drive shaft housing and having a cowling disposed over the power head with a lower open end secured in superimposed relation to the upper end of the drive shaft housing, a drive shaft neck depending from the power head through the superimposed cowling and housing openings, a jacketed exhaust stack laterally spaced from the neck and depending from the power head through the superimposed cowling and housing openings and having an encircling exhaust cooling chamher in the jacket thereof with at least one discharge opening in the lower end of the jacket, a pair, of vertically spaced semi-flexible diaphragms spanning the opening between the housing and the cowling and each having an opening accommodating the drive shaft neck and an opening accommodating the exhaust stack above the said discharge opening and being in sealing engagement with the neck and stack, respectively, said diaphragms being sufficiently flexible to accommodate power head vibrations imparted to the neck and stack and suificiently stiff to provide lateral support for the power head, said diaphragms defining a diaphragm cooling chamber therebe- 7 tween, and ports connecting-the exhaust cooling chamber to the diaphragm cooling'chamber.

.8. In an outboard motor adapted to have the lower end immersed in water and having a water-cooled power head disposed within a power head chamber defined by an inverted cup-shaped cowling assembly and being elastically mounted upon the open upper end of a housing defining an exhaust chamber, the lower end of the cowling assembly being seoured to the exhaust housing with an exhaust uni-t depending from the power head into the exhaust housing, a pair of stabilizing and sealing members arranged in vertically spaced relation surrounding the exhaust unit and being sealed to the exhaust unit to separate the power head chamber from the exhaust chamher and defining a cooling chamber therebetween, said.

member being disposed to provide lateral stability to the mounting of the power 'head and having limited flexibility for accommodating and absorbing power head vibrations imparted to the exhaust unit, and means connecting said cooling chamber to the water cooling system of said power head.

References Cited in the file of this patent UNITED STATES PATENTS 2,478,489 Kelson Aug. 9, 1949 2,506,271 Kiekhaefer May 2, 1950 2,757,650 Holley Aug. 7, 1956 2,909,031 Kiekhaefer Oct. 20, 1959 

